ABSTRACT
Herein, a novel copper selenide/zinc selenide/Nitrogen-doped carbon (Cu2Se/ZnSe/NC) sphere was constructed via a combination of cation exchange, selenization and carbonization approaches with zinc-based metal-organic frameworks (ZIF-8) as precursor for sulfadiazine (SDZ) removal. Compared with the ZnSe/NC, the defective Cu2Se/ZnSe interface in the optimizing Cu-ZnSe/NC2 sample caused a remarkably improved adsorption performance. Notably, the adsorption capacity of 129.32 mg/g was better than that of mostly reported adsorbents for SDZ. And the adsorption referred to multiple-layer physical-chemical process that was spontaneous and exothermic. Besides, the Cu-ZnSe/NC2 displayed fast adsorption equilibrium of about 20 min and significant anti-interference ability for inorganic ions. Specially, the adsorbent possessed excellent stability and reusability, which could also be applied for rhodamine B (RhB), methylene blue (MB), and methyl orange (MO) dyes removal. Ultimately, the charge redistribution of Cu2Se/ZnSe interface greatly contributes the superior adsorption performance for SDZ, in which electrostatic attraction occupied extremely crucial status as compared to π-π electron-donor-acceptor (π-π EDA) interaction and hydrogen bonding (H-bonding), as revealed by the density function theory (DFT) calculations and experimental results. This study can provide a guideline for design of high-efficient adsorbent with interfacial charge redistribution.
ABSTRACT
Antimony selenide (Sb2 Se3 ) is a highly promising photovoltaic material thanks to its outstanding optoelectronic properties, as well as its cost-effective and eco-friendly merits. However, toxic CdS is widely used as an electron transport layer (ETL) in efficient Sb2 Se3 solar cells, which largely limit their development toward market commercialization. Herein, an effective green Cd-free ETL of SnOx is introduced and deposited by atomic layer deposition method. Additionally, an important post-annealing treatment is designed to further optimize the functional layers and the heterojunction interface properties. Such engineering strategy can optimize SnOx ETL with higher nano-crystallinity, higher carrier density, and less defect groups, modify Sb2 Se3 /SnOx heterojunction with better interface performance and much desirable "spike-like" band alignment, and also improve the Sb2 Se3 light absorber layer quality with passivated bulk defects and prolonged carrier lifetime, and therefore to enhance carrier separation and transport while suppressing non-radiative recombination. Finally, the as-fabricated Cd-free Mo/Sb2 Se3 /SnOx /ITO/Ag thin-film solar cell exhibits a stimulating efficiency of 7.39%, contributing a record value for Cd-free substrate structured Sb2 Se3 solar cells reported to date. This work provides a viable strategy for developing and broadening practical applications of environmental-friendly Sb2 Se3 photovoltaic devices.
ABSTRACT
In this work, we performed a systematic comparison of different duration of solvent vapor annealing (SVA) treatment upon state-of-the-art PM6:SY1 blend film, which is to say for the first time, the insufficient, appropriate, and over-treatment's effect on the active layer is investigated. The power conversion efficiency (PCE) of corresponding organic solar cell (OSC) devices is up to 17.57% for the optimized system, surpassing the two counterparts. The properly tuned phase separation and formed interpenetrating network plays an important role in achieving high efficiency, which is also well-discussed by the morphological characterizations and understanding of device physics. Specifically, these improvements result in enhanced charge generation, transport, and collection. This work is of importance due to correlating post-treatment delicacy, thin-film morphology, and device performance in a decent way.
ABSTRACT
Antimony selenide (Sb2Se3) has been widely investigated as a promising absorber material for photovoltaic devices. However, low open-circuit voltage (Voc) limits the power conversion efficiency (PCE) of Sb2Se3-based cells, largely due to the low-charge carrier density. Herein, high-quality n-type (Tellurium) Te-doped Sb2Se3 thin films were successfully prepared using a homemade target via magnetron sputtering. The Te atoms were expected to be inserted in the spacing of (Sb4Se6)n ribbons based on increased lattice parameters in this study. Moreover, the thin film was found to possess a narrow and direct band gap of approximately 1.27 eV, appropriate for harvesting the solar energy. It was found that the photoelectric performance is related to not only the quality of films but also the preferred growth orientation. The Te-Sb2Se3 film annealed at 325 °C showed a maximum photocurrent density of 1.91 mA/cm2 with a light intensity of 10.5 mW/cm2 at a bias of 1.4 V. The fast response and recovery speed confirms the great potential of these films as excellent photodetectors.
ABSTRACT
A new type of solar cell based on Cu-doped (p-type) and I-doped (n-type) Sb2Se3 has been designed and fabricated using magnetron sputtering with two different thicknesses of absorber. The overall objective is for better understanding the charge recombination mechanism, especially at the interface region. The investigation has been specifically performed using IMPS (intensity modulated photocurrent spectroscopy), IMVS (intensity modulated photovoltage spectroscopy), and diode characterizations. It has been found that an increase of the absorber thickness leads to a shorter carrier lifetime, but longer diffusion length and lower trap density, resulting in significantly better performance. Furthermore, it is demonstrated that trap-assisted recombination does not affect the short-circuit current density (Jsc), but significantly decreases the open-circuit voltage (Voc). As a result, an encouraging power conversion efficiency (PCE) of 2.41%, fill factor (FF) of 41%, Jsc of 20 mA/cm2, and Voc of 294 mV are obtained. Most importantly, key parameters for further increasing the PCE have been identified.
